Question: Simplify the following expression: $t = \dfrac{x}{3} - \dfrac{x}{10}$
Answer: In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $3$ and $10$ $\lcm(3, 10) = 30$ $ t = \dfrac{10}{10} \cdot \dfrac{x}{3} - \dfrac{3}{3} \cdot \dfrac{x}{10} $ $t = \dfrac{10x}{30} - \dfrac{3x}{30}$ $t = \dfrac{10x -3x}{30}$ $t = \dfrac{7x}{30}$